Field
The present disclosure relates to network management. More specifically, the present disclosure relates to a method and system for detecting a forwarding path failure based on a bidirectional forwarding detection (BFD) protocol in a distributed architecture.
Related Art
The exponential growth of the Internet has made it a popular delivery medium for multimedia applications, such as video on demand and television. Such applications have brought with them an increasing demand for bandwidth. As a result, equipment vendors race to build larger and faster switches with versatile capabilities, such as service insertion and provisioning, to move more traffic efficiently. However, the size of a switch cannot grow infinitely. It is limited by physical space, power consumption, and design complexity, to name a few factors. Furthermore, switches with higher capability are usually more complex and expensive. More importantly, because an overly large and complex system often does not provide economy of scale, simply increasing the size and capability of a switch may prove economically unviable due to the increased per-port cost.
A flexible way to improve the scalability of a switch system is to build a fabric switch. A fabric switch is a collection of individual member switches, e.g., a network of interconnected switches. These member switches form a single, logical switch that can have an arbitrary number of ports and an arbitrary topology. As demands grow, customers can adopt a “pay as you grow” approach to scale up the capacity of the fabric switch.
Meanwhile, layer-2 (e.g., Ethernet) switching technologies continue to evolve. More routing-like functionalities, which have traditionally been the characteristics of layer-3 (e.g., Internet Protocol or IP) networks, are migrating into layer-2. As Internet traffic is becoming more diverse, virtual computing in a network is becoming progressively more important as a value proposition for network architects. For example, a traditional bidirectional forwarding detection (BFD) protocol is a network protocol used to rapidly detect faults between adjacent forwarding engines, e.g., two forwarding engines connected by a link or two connected interfaces. A BFD session can be established between two endpoints that exchange BFD control packets over a particular link at a pre-negotiated interval. BFD is described in RFC 5880, “Bidirectional Forwarding Detection,” by D. Katz and D. Ward, June 2010, the entirety of which is hereby incorporated by reference. However, some issues remain unsolved when using BFD as a fault detection mechanism in a distributed architecture such as a fabric switch or a virtual cluster switch (VCS) cluster.